Conventionally, fluorine gas is used in the semiconductor manufacturing process and so on for material cleaning, surface modification, and other purposes. While the fluorine gas itself is used in some cases, a variety of fluorine-based gases synthesized based on the fluorine gas, such as NF3 (nitrogen trifluoride) gas, NeF (neon fluoride) gas, and ArF (argon fluoride) gas, may also be used in other cases.
For supplying fluorine gas stably in such sites, a fluorine gas generation device that generates fluorine gas by electrolysis of HF (hydrogen fluoride), for example, is used.
The fluorine gas generation device disclosed in Patent Document 1 includes an electrolyzer. The interior of the electrolyzer is divided by a partition wall into a cathode chamber and an anode chamber. In the electrolyzer, an electrolytic bath is formed with a KF-HF-based mixed molten salt. A cathode is disposed in the cathode chamber, and an anode is disposed in the anode chamber. HF is supplied through an HF supply line to the electrolytic bath in the electrolyzer for electrolysis of HF, whereby hydrogen gas is generated from the cathode and fluorine gas is generated from the anode in the electrolyzer.
At the top of the cathode chamber, an outlet for hydrogen gas is provided. The hydrogen gas generated in the cathode chamber exits from the outlet and is discharged through a hydrogen gas line on the cathode side. The hydrogen gas line is provided with an automatic valve and an HF adsorption column. The HF adsorption column is packed with granular NaF (sodium fluoride) pellets. This enables HF mixed in the hydrogen gas to be adsorbed by the NaF pellets in the HF adsorption column and, thus, removed from the hydrogen gas.
At the top of the anode chamber, an outlet for fluorine gas is provided. The fluorine gas generated in the anode chamber exits from the outlet and is discharged through a fluorine gas line. The fluorine gas line is provided with an HF adsorption column and an automatic valve. As in the hydrogen gas line, HF mixed in the fluorine gas is adsorbed by the NaF pellets in the HF adsorption column and, thus, removed from the fluorine gas.
On the fluorine gas line, a compressor unit is provided on the downstream of the HF adsorption column and the automatic valve.
In each of the cathode chamber and anode chamber, a pressure gauge for measuring the pressure in the corresponding chamber is provided. The automatic valves disposed on the hydrogen gas line and fluorine gas line open/close in accordance with the pressure values measured by the pressure gauges.
The automatic valve on the fluorine gas line opens when the pressure inside the anode chamber is higher than atmospheric pressure, causing the fluorine gas in the anode chamber to be sucked through the fluorine gas line into the compressor unit. On the other hand, the automatic valve on the fluorine gas line closes when the pressure inside the anode chamber is lower than atmospheric pressure.
[Patent Document 1] JP 2004-52105 A